at_utils.h

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/*
 * Copyright (c) 2019 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
 */
 
#ifndef AT_UTILS_H__
#define AT_UTILS_H__
 
#include <zephyr/types.h>
#include <stddef.h>
#include <ctype.h>
 
#define AT_PARAM_SEPARATOR ','
#define AT_RSP_SEPARATOR ':'
#define AT_CMD_SEPARATOR '='
#define AT_CMD_READ_TEST_IDENTIFIER '?'
#define AT_CMD_BUFFER_TERMINATOR 0
#define AT_CMD_STRING_IDENTIFIER '\"'
#define AT_STANDARD_NOTIFICATION_PREFIX '+'
#define AT_PROP_NOTIFICATION_PREFX '%'
#define AT_CUSTOM_COMMAND_PREFX '#'
 
static inline bool is_notification(char chr)
{
        if ((chr == AT_STANDARD_NOTIFICATION_PREFIX) ||
            (chr == AT_PROP_NOTIFICATION_PREFX) ||
            (chr == AT_CUSTOM_COMMAND_PREFX)) {
                return true;
        }
 
        return false;
}
 
static inline bool is_valid_command_char(char chr)
{
        if (isalpha((int)chr) || isdigit((int)chr)) {
                return true;
        }
 
        return false;
}
 
static inline bool is_valid_notification_char(char chr)
{
        chr = toupper((int)chr);
 
        if (((chr >= 'A') && (chr <= 'Z')) || (chr == '_')) {
                return true;
        }
 
        return false;
}
 
static inline bool is_terminated(char chr)
{
        if (chr == AT_CMD_BUFFER_TERMINATOR) {
                return true;
        }
 
        return false;
}
 
static inline bool is_separator(char chr)
{
        if ((chr == AT_PARAM_SEPARATOR) || (chr == AT_RSP_SEPARATOR) ||
            (chr == AT_CMD_SEPARATOR)) {
                return true;
        }
 
        return false;
}
 
static inline bool is_lfcr(char chr)
{
        if ((chr == '\r') || (chr == '\n')) {
                return true;
        }
 
        return false;
}
 
static inline bool is_dblquote(char chr)
{
        if (chr == '"') {
                return true;
        }
 
        return false;
}
 
static inline bool is_array_start(char chr)
{
        if (chr == '(') {
                return true;
        }
 
        return false;
}
 
static inline bool is_array_stop(char chr)
{
        if (chr == ')') {
                return true;
        }
 
        return false;
}
 
static inline bool is_number(char chr)
{
        if (isdigit((int)chr) || (chr == '-') || (chr == '+')) {
                return true;
        }
 
        return false;
}
 
static inline bool is_command(const char *str)
{
        if (strlen(str) < 2) {
                return false;
        }
 
        if ((toupper((int)str[0]) != 'A') || (toupper((int)str[1]) != 'T')) {
                return false;
        }
 
        /* Third character has be one of the command special characters.
         * The special case is a lone "AT" command.
         */
        if ((str[2] == AT_STANDARD_NOTIFICATION_PREFIX) ||
            (str[2] == AT_PROP_NOTIFICATION_PREFX) ||
            (str[2] == AT_CUSTOM_COMMAND_PREFX) ||
            is_lfcr(str[2]) || is_terminated(str[2])) {
                return true;
        }
 
        return false;
}
 
static bool is_clac(const char *str)
{
        /* skip leading <CR><LF>, if any, as check not from index 0 */
        while (is_lfcr(*str)) {
                str++;
        }
 
        if (strlen(str) < 4) {
                return false;
        }
 
        if ((toupper(str[0]) != 'A') || (toupper(str[1]) != 'T')) {
                /* Not an AT command */
                return false;
        }
 
        if ((toupper(str[2]) != '+') && (toupper(str[2]) != '%')) {
                /* Neither AT+ nor AT% */
                return false;
        }
 
        if ((toupper(str[2]) == '%') && (toupper(str[3]) == 'X')) {
                /* Ignore AT%X to avoid false detect (read resp XCOEX0 etc.) */
                return false;
        }
 
        return true;
}
#endif /* AT_UTILS_H__ */